1 8oS THE PICARIAN BIRDS 



where it occurs in Western Abyssinia, and on the west coast from Senegambia to 

 the River Niger. Two other members of the genus are known. 



As in the preceding genus, this nightjar (Cosmetomis vexillarius) 

 Standard- jjas an elongation of the primary quills, of which the seventh and 



eighth are greatly developed, while the ninth is prolonged into a 

 Nightjar 



streamer which floats behind the bird as it flies. The shaft, however, 



is not bare as in the Leona nightjar, but feathered throughout its whole extent. 

 This bird is an inhabitant of Africa, and its range extends from Equatorial Africa 

 westward to the Benue river and Fernando Po, and south throughout Eastern 

 Africa to the Zambezi and Damaraland. The following account of this nightjar 

 has been published by Sir J. Kirk, who met with it in Nyassaland, and writes that it 

 " was first observed about three hundred miles up the Zambezi, a little above Tete, 

 on the Keihrabassa rapids, in November, 1858, and was there decidedly common. 

 It was again met with on the western side of Lake Nyassa, where in September and 

 October, it was very plentiful, being seen in flocks of from fifteen to twenty. It 

 was also common at Chibisa on the Shire, in latitude 16 south. It was only 

 during the months from October to January that the singular prolongation 

 of the wing feathers was observed; these are peculiar to the males. Like 

 other nightjars, the habits oj: these birds are crepuscular. When startled during 

 the daytime from the ground, where they always rest, they fly swiftly for a little 

 distance, and again settle, but are extremely difficult to follow with the eye. Not 

 so with the males in full plumage. In their case there is no difficulty; their flight 

 is evidently retarded, and they become prominent objects from the long streamers 

 waving behind them. A deviation from the usual habits of the bird was observed 

 when cruising on the Nyassa Lake. On two occasions, being overtaken in a gale, 

 and riding out a short but dangerous sea, which set in and raised a surf on the 

 shore, through which it was impossible to land, the male birds came off in flocks of 

 about fifteen and flew over the surface of the water. On no other occasion have I 

 seen them take wing of their own accord, or keep on the wing during the day." 



South America is the home of a group of nightjars remarkable for 

 N . , . their enormously developed forked tails; while in Africa there is also a 

 genus (Scotomis] which has an elongated tail, longer than the body 

 of the bird itself, the feathers gradually decreasing in length till the outside ones 

 are the shortest. In South America, the genus under consideration has the outer 

 tail feathers produced, and the two central ones also, the next pair being the short- 

 est. In Macrop salis, however, the outside pair of tail feathers are produced to 

 an enormous length and form a train, the feathers gradually reduced in size toward 

 the middle of the tail, the two centre -ones being the shortest. Of the Aigentine 

 fork-tailed nightjar (Hydropsalis furcifera}, Durnford states that it is not uncommon 

 near Buenos Ayres in spring and autumn, living on the ground in damp situations 

 where the grass is long and thick enough to afford some slight cover, and is gener- 

 ally observed in parties of four or five individuals. Its flight is noiseless, and 

 performed by jerky, erratic movements. In Entre Rios, Mr. J. B. Barrows found 

 it common in summer, 'arriving in August and leaving in May; and he states that 

 "while hunting capivaras and armadillos by moonlight, I had frequently good 



